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| Titel |
Environmental characterisation of a major radioxenon source in Europe |
| VerfasserIn |
P. R. J. Saey, A. Ringbom, A. Becker, J. Camps, N. Paquet, M. Sonck, T. Taffary, K. van der Meer, B. Verboomen, M. Zähringer |
| Konferenz |
EGU General Assembly 2009
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 11 (2009) |
| Datensatznummer |
250027247
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| Zusammenfassung |
| Abstract
In the framework of the verification of the Comprehensive Nuclear-Test-Ban Treaty
(CTBT) the atmospheric background of environmental radioxenon has been studied. It was
recently shown that radiopharmaceutical facilities (RPF) have a major contribution to the
general background of 133Xe and other xenon isotopes both in the northern and southern
hemisphere. The daily International Monitoring System (IMS) noble gas measurements
around the globe are influenced from such anthropogenic sources that could hide relevant
radioxenon signals.
To distinguish a nuclear explosion from releases from civil nuclear facilities, not only the
activity concentration but also the ratio of different radioxenon isotopes (131mXe, 133mXe,
133Xe and 135Xe) plays a crucial role, since the ratios can be used to discriminate source
types.
Theoretical release and ratio studies were recently published, but no high-sensitive
measurements in and close to radiopharmaceutical facilities have ever been performed.
During the summer of 2008, a three week field campaign was carried out in the region
around the Belgian radiopharmaceutical facility IRE in Fleurus, the world third largest one.
The scope was to obtain the activity concentration of the releases and the isotopic
composition. Two 6-hour noble gas measurements, using mobile SAUNA sampling
equipment were collected each day at different distances from the facility (1 – 100 km). The
sampling locations were guided by atmospheric dispersion model results. Three
samples from the stack itself were also collected. All 38 samples were shipped
after collection to and measured with a SAUNA at the laboratory in Stockholm,
Sweden.
The environmental concentrations of 133Xe were measured and found to be in the range
between 0.7 – 4 105 mBq/m3. Nine samples contained all four CTBT relevant radioxenon
isotopes. The concentrations of the stack spike samples were in the range 2 109 – 4 1010
mBq/m3. This corresponds to a daily release of around 1 TBq. This is consistent with
literature and is well below exposure guidelines and therefore not dangerous to
the public, but high enough to increase radioxenon background in wide regions
around such facilities especially given the high sensitivity of the CTBT monitoring
systems.
In a simple model the measured concentrations are fitted versus the distance from IRE
and the resulting source term agrees reasonably well with the concentration of the measured
stack samples.
This paper further compares the environmental field measurements made with reported
stack releases from the facility, with measurements from the Belgian national Telerad
network as well with long distance measurements at the Schauinsland Mountain near
Freiburg, Germany and at Bruyères-le-Ch-tel, near Paris, France.
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Disclaimer
The views expressed in this publication are those of the authors and do not necessarily
reflect the views of the CTBTO Preparatory Commission or any of the institutions mentioned
herein.
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Acknowledgement
This project is performed in the framework of European Council Joint Action no.
2007/468/CFSP on support for activities of the Preparatory Commission of the
Comprehensive Nuclear-Test-Ban Treaty Organisation (CTBTO) monitoring and verification
capabilities in the framework of the implementation of the European Union Strategy against
Proliferation of Weapons of Mass Destruction. |
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