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U.S. Department of Energy
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Nondestructive assay holdup measurements with the Ortec detective

Conference ·
OSTI ID:989774
Wing 4 of the Chemistry and Metallurgy Research facility at Los Alamos National Laboratory is to be downgraded from a Hazard Category 2 Nuclear Facility to a Hazard Category 3 Radiological Facility. Survey and holdup measurements are used to ensure that the total contamination levels present in the facility do not contribute enough activity to go above the Hazard Category 3 threshold quantities. Additionally, the measurement information provides an understanding of the cleanup and the equipment removal needs for the next step of decontaminating and decommissioning of the site. The Chemistry and Metallurgy Research (CMR) facility has been housing the research and experimental activities for analytical chemistry, plutonium and uranium chemistry, and metallurgy since the start of the Los Alamos National Laboratory. It is currently being replaced by the new Chemistry and Metallurgy Research Replacement facilities. As a result, the CMR is gradually closing and/or downgrading to a nonnuclear facility. In 2008, the Safeguards Science and Technology group, N-1, was assigned the task of doing survey and holdup measurements of Wing 4 of the CMR. The goal of the measurements is to provide defensible measurement data for Wing 4 of the CMR Building to be downgraded from a Hazard Category 2 Nuclear Facility to below a Hazard Category 3 Radiological Facility. In addition, the measurement information would provide an understanding of the cleanup and the equipment removal needs for the next step of decontaminating and decommissioning the site. The large areal olume of the site and the high intensity of the high-energy gamma rays of thorium, either from the background or the contaminated objects in the measured room or the adjacent rooms, present some challenges in the holdup measurements. Typical holdup techniques of point source, line, or area measurement do not work well. In order to speed up the measurement time and to accuralely account for all the isotopes present in the facility, we used a new technique that we tentatively named 'Room Holdup Measurement' to do holdup measurements of the site. This technique uses the portable, electric-cooled high-purity germanium detectors from Ortec (the Detectives) to measure the activities of the isotopes.
Research Organization:
Los Alamos National Laboratory (LANL)
Sponsoring Organization:
DOE
DOE Contract Number:
AC52-06NA25396
OSTI ID:
989774
Report Number(s):
LA-UR-09-03384; LA-UR-09-3384
Country of Publication:
United States
Language:
English