Final evaluation of characterizing pipe-over-pack containers using high efficiency neutron counters Page: 2 of 15
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WM' 09 Conference, March 1-March 5, 2009, Tucson, AZ
Final Evaluation of Characterizing Pipe-Over-Pack Containers Using High
Efficiency Neutron Counters
S.B. Stanfield', J.R. Wachter2, D.L. Cramer2, J.P Harvill3, P.H. Carson4
AREVA Federal Services
4800 Hampden Lane Suite 100 Bethesda, MD 20814
800 Research Pkwy, Meriden, CT 06450
Washington TRU Solutions3
Los Alamos National Laboratory4
Nondestructive assay (NDA) measurements of Transuranic (TRU) waste at Los Alamos
National Laboratory (LANL) packed in Pipe-Over-Pack Containers (POC) contain a number of
complexities. The POC is highly attenuating to both gamma rays and neutrons which presents a
difficult waste matrix for correct quantification of material in the container. Currently there are
a number of POC containers at LANL that require evaluation for shipment to the Waste
Isolation Pilot Plant (WIPP) in Carlsbad, NM. Updated data has been evaluated that finalizes
the evaluation of characterizing Pipe-Over-Pack Containers.
Currently at LANL, a single instrument has been used to explore the appropriateness of both
passive neutron and quantitative gamma ray methods for measuring POC's. The passive
neutron approach uses the Reals coincidence count rate to establish plutonium mass and other
parameters of interest for TRU waste. The quantitative gamma ray method assumes a
homogeneous distribution of radioactive source material with the surrounding material
throughout the drum volume. Drums are assayed with a calibration based on the known
density of the matrix. Both methods are supplemented by a simultaneous isotopic
measurement using Multi-Group Analysis (MGA) to determine the plutonium isotopic
composition. If MGA fails to provide a viable isotopic result Fixed Energy Response function
Analysis with Multiple efficiencies (FRAM) has been used to replace the MGA results.
Acceptable Knowledge (AK) may also be used in certain instances.
This report will discuss the two methods in detail. Included in the discussion will be
descriptions of the setup parameters and calibration techniques for the instrument. A number
of test measurements have been performed to compare HENC data with certified historical
data. Empty POCs loaded with known sources have also been measured to determine the
viability of the technique. A comparison between calorimetry data, historical measurements
and HENC data will also be performed. The conclusion will show that the current calibration
on the HENC units is viable for analysis of POCs.
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Carson, Pete; Stanfield, Sean B; Wachter, Joe; Cramer, Doug & Harvill, Joe. Final evaluation of characterizing pipe-over-pack containers using high efficiency neutron counters, article, January 1, 2009; [New Mexico]. (https://digital.library.unt.edu/ark:/67531/metadc931045/m1/2/: accessed March 24, 2019), University of North Texas Libraries, Digital Library, https://digital.library.unt.edu; crediting UNT Libraries Government Documents Department.