Screening and Spectral Summing of LANL Empty Waste Drums - 13226
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)
- Pajarito Scientific Corporation, Santa Fe, New Mexico 87505 (United States)
Empty 55-gallon drums that formerly held transuranic (TRU) waste (often over-packed in 85- gallon drums) are generated at LANL and require radiological characterization for disposition. These drums are typically measured and analyzed individually using high purity germanium (HPGe) gamma detectors. This approach can be resource and time intensive. For a project requiring several hundred drums to be characterized in a short time frame, an alternative approach was developed. The approach utilizes a combination of field screening and spectral summing that was required to be technically defensible and meet the Nevada Nuclear Security Site (NNSS) Waste Acceptance Criteria (WAC). In the screening phase of the operation, the drums were counted for 300 seconds (compared to 600 seconds for the typical approach) and checked against Low Level (LL)/TRU thresholds established for each drum configuration and detector. Multiple TRU nuclides and multiple gamma rays for each nuclide were evaluated using an automated spreadsheet utility that can process data from up to 42 drums at a time. Screening results were reviewed by an expert analyst to confirm the field LL/TRU determination. The spectral summing analysis technique combines spectral data (channel-by-channel) associated with a group of individual waste containers producing a composite spectrum. The grouped drums must meet specific similarity criteria. Another automated spreadsheet utility was used to spectral sum data from an unlimited number of similar drums grouped together. The composite spectrum represents a virtual combined drum for the group of drums and was analyzed using the SNAP{sup TM}/Radioassay Data Sheet (RDS)/Batch Data Report (BDR) method. The activity results for a composite virtual drum were divided equally amongst the individual drums to generate characterization results for each individual drum in the group. An initial batch of approximately 500 drums were measured and analyzed in less than 2 months in 2011. A second batch of approximately 500 more drums were measured and analyzed during the following 2 1/2 months. Four different HPGe detectors were employed for the operation. The screening and spectral summing approach can reduce the overall measurement and analysis time required. However, developing the technical details and automation spreadsheets requires a significant amount of expert time prior to beginning field operations and must be considered in the overall project schedule. This approach has continued to be used for characterizing several hundred more empty drums in 2012 and is planned to continue in 2013. (authors)
- Research Organization:
- WM Symposia, 1628 E. Southern Avenue, Suite 9-332, Tempe, AZ 85282 (United States)
- OSTI ID:
- 22224980
- Report Number(s):
- INIS-US-13-WM-13226; TRN: US14V0429045935
- Resource Relation:
- Conference: WM2013: Waste Management Conference: International collaboration and continuous improvement, Phoenix, AZ (United States), 24-28 Feb 2013; Other Information: Country of input: France; 4 refs.
- Country of Publication:
- United States
- Language:
- English
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