Comparison of Shuffler and Segmented Gamma Scanner Measurements of 55-Gallon Drums Containing HEU Embedded in Varied Matrices.
- Jon R.
- Linda V.
- Cipriano D.
- John R.
- Georgiana M.
- Stephen J.
Many forms of nuclear waste materials are constantly generated at Los Alamos Chemical and Metallurgical Research (CMR) Facility. For disposal, accounting of the nuclear material must be done. We were recently tasked with measuring sixteen 55-gallon drums, each containing about 150 to 250 grams of HEU. The lower two-thirds of the drums consisted mostly of paper, plastics, and other combustibles. The HEU in this bulk waste had been previously assayed using a segmented gamma scanner (SGS) and ranged from 1 to 20 grams per drum. The drums were later re-opened and specific packages of HEU waste solids, mostly polyethylene bottles filled with uranium oxide and/or fluoride, were placed on top of the bulk waste. The number of bottles ranged from one to seven with an additional {sup 235}U mass between 150 to 230 grams per drum. Although many of these additional mass values were based on results from an old chemical analysis, they are expected to be reasonably accurate. We counted the drums on the SGS and shuffler instruments. The results were biased low on the SGS which was calibrated for normal combustible waste (not bottles embedded in waste) and biased high on the shuffler calibrated for small cans of oxide. The biases were caused by the differences among the calibration standards and the drums. This paper is a study of the nature of these biases, providing corrections and comparing the resulting performance characteristics of the instruments. This effort was greatly enhanced by having photographic as well as real-time radiographic information on many of the drums contents. A new software tool, recently developed at Los Alamos to calculate shuffler count rates accurately and generate bias correction factors, was applied to these drums. The application of the calculational tool to generate bias corrections for these types of matrices is described. The results from the two instruments are compared and discussed.
- Research Organization:
- Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)
- Sponsoring Organization:
- USDOE
- OSTI ID:
- 976193
- Report Number(s):
- LA-UR-02-3246; TRN: US1002871
- Resource Relation:
- Conference: Submitted to: 43rd Annual Meeting of the Institute of Nuclear Materials Management (INMM) held June 23-27, 2002 at Orlando, FL
- Country of Publication:
- United States
- Language:
- English
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