Discrimination Between Anthropogenic Sources of Atmospheric Radioxenon
The Automated Radioxenon Analyzer/Sampler (ARSA) has been deployed at several locations throughout the world: Richland, WA; New York City, NY; Orlando, FL; Charlottesville, VA; Freiburg, Germany, and is en route to Guangzhou, China. In each of these locations the ARSA has measured varying air concentrations of 133Xe, and in most instances 131mXe and 135Xe, which are indicative of nuclear explosions. Anthropogenic radioxenon sources lead to high background levels of three of the four radioxenon isotopes of interest measured by the ARSA, making it difficult to sort ambient radioxenon emissions from clandestine underground nuclear explosions using concentrations alone. High concentrations and multiple isotope identification within a single sample are good measures of potentially suspect radioxenon emissions. Utilizing the ratios of the concentrations of 135Xe to 133Xe and 133Xe to 133mXe enables a distinction between routine emissions and clandestine underground nuclear detonations. Analyses to date indicate that concentration levels, multiple radioxenon isotopes in a single sample, the presence of 133mXe and isotopic ratios will all be good indicators of clandestine underground nuclear explosions and the combination of two or more of these measures will provide strong evidence of such activities. This paper will explore both the concentration data collected to date from each site and the usefulness of ratios in discriminating between reactor effluents and underground nuclear tests. The measured radioxenon concentrations represent an ambient background of some of the planned deployment locations outlined by the Provisional Technical Secretariat (PTS). These emissions can be attributed to nuclear power reactor operations, hospital use of 133Xe for medical testing, and fuel reprocessing activities to a lesser extent. In all instances the measured concentrations for 133Xe have been well above the 1 mBq/m3 minimum detectable concentration (MDC) requirement adopted by the Comprehensive Nuclear-Test-Ban-Treaty Organization Preparatory Commission. For several of the deployed locations (Florida, Charlottesville, Germany, and New York City) the ARSA, which has a 133Xe MDC below 0.2 mBq/m3, had a significant number of samples with 133Xe concentrations above the 0.2 mBq/m3 MDC level. Though no MDC’s have been set for 131mXe and 133mXe the PTS required that any deployed system be capable of measuring them and the ARSA has achieved MDC’s for the two metastable isotopes of less than 0.3 mBq/m3 and for 135Xe below 1.0 mBq/m3. The measured concentrations and the identification of multiple isotopes within a single sample at all of the sampling locations merited further analysis of the data to determine the isotopic ratios from non-nuclear detonation sources.
- Research Organization:
- Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- AC05-76RL01830
- OSTI ID:
- 985605
- Report Number(s):
- PNNL-SA-38517; TANSAO; NN2003000; TRN: US1006167
- Journal Information:
- Transactions of the American Nuclear Society, 87:89-90, Vol. 87; ISSN 0003-018X
- Country of Publication:
- United States
- Language:
- English
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