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Title: Plutonium Assay in Soil at the BRC Threshold

Abstract

The Atomic Weapons Establishment (AWE) at Aldermaston has investigated the performance of low and high-resolution gamma-ray detectors for plutonium (Pu) assay in soil at the UK Below Regulatory Concern (BRC) threshold (0.4 Bq/g above the natural background activity level). The goal was a rapid and economical technique for sorting large volumes of lightly contaminated soils into above and BRC fractions. The strategy involved utilizing the relatively high yield 60 keV emission from Am-241 ingrowth (Pu-241 daughter) and known isotopic ratios. This paper covers the determination of detector response factors for an Am-241 source positioned at various locations within a circular tray of soil. These factors were weighted, according to the relative volumes that they represent, in order to derive a uniform response factor and quantify the systematic error for non-uniform activity distributions. Detection limits and random errors were also derived from the counting data. The high-resolution detector was shown to have the best detection levels and lowest systematic and random errors. However, uncertainties for non-uniform distributions of contamination were relatively large. Hence, analyzing soils at the BRC threshold would only be feasible if contamination was well distributed throughout the soil sample being monitored. Fortunately, contaminated land at AWE is generallymore » homogeneous and so the technique has wide applicability.« less

Authors:
Publication Date:
Research Org.:
AWE, Aldermaston, Reading, Berkshire, RG7 4PR (GB)
Sponsoring Org.:
none (US)
OSTI Identifier:
827183
Resource Type:
Conference
Resource Relation:
Conference: Waste Management 2003 Symposium, Tucson, AZ (US), 02/23/2003--02/27/2003; Other Information: PBD: 25 Feb 2003
Country of Publication:
United States
Language:
English
Subject:
43 PARTICLE ACCELERATORS; 45 MILITARY TECHNOLOGY, WEAPONRY, AND NATIONAL DEFENSE; 54 ENVIRONMENTAL SCIENCES; 38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEAR CHEMISTRY; CONTAMINATION; DETECTION; NUCLEAR WEAPONS; PERFORMANCE; PLUTONIUM; SENSITIVITY; SOILS; SORTING; WASTE MANAGEMENT

Citation Formats

Miller, T. Plutonium Assay in Soil at the BRC Threshold. United States: N. p., 2003. Web.
Miller, T. Plutonium Assay in Soil at the BRC Threshold. United States.
Miller, T. Tue . "Plutonium Assay in Soil at the BRC Threshold". United States. https://www.osti.gov/servlets/purl/827183.
@article{osti_827183,
title = {Plutonium Assay in Soil at the BRC Threshold},
author = {Miller, T},
abstractNote = {The Atomic Weapons Establishment (AWE) at Aldermaston has investigated the performance of low and high-resolution gamma-ray detectors for plutonium (Pu) assay in soil at the UK Below Regulatory Concern (BRC) threshold (0.4 Bq/g above the natural background activity level). The goal was a rapid and economical technique for sorting large volumes of lightly contaminated soils into above and BRC fractions. The strategy involved utilizing the relatively high yield 60 keV emission from Am-241 ingrowth (Pu-241 daughter) and known isotopic ratios. This paper covers the determination of detector response factors for an Am-241 source positioned at various locations within a circular tray of soil. These factors were weighted, according to the relative volumes that they represent, in order to derive a uniform response factor and quantify the systematic error for non-uniform activity distributions. Detection limits and random errors were also derived from the counting data. The high-resolution detector was shown to have the best detection levels and lowest systematic and random errors. However, uncertainties for non-uniform distributions of contamination were relatively large. Hence, analyzing soils at the BRC threshold would only be feasible if contamination was well distributed throughout the soil sample being monitored. Fortunately, contaminated land at AWE is generally homogeneous and so the technique has wide applicability.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {2003},
month = {2}
}

Conference:
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