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| Titel |
Monitoring of reported sudden emission rate changes of major radioxenon emitters in the northern and southern hemispheres in 2008 to assess their contribution to the respective radioxenon backgrounds |
| VerfasserIn |
P. R. J. Saey, M. Auer, A. Becker, S. Colmanet, E. Hoffmann, M. Nikkinen, C. Schlosser, M. Sonck |
| 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 |
250026089
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| Zusammenfassung |
| Abstract
Atmospheric radioxenon monitoring is a key component of the verification of the
Comprehensive Nuclear-Test-Ban Treaty (CTBT). Radiopharmaceutical production facilities
(RPF) have recently been identified of emitting the major part of the environmental
radioxenon measured at globally distributed monitoring sites deployed to strengthen the
radionuclide part of the CTBT verification regime. Efforts to raise a global radioxenon
emission inventory revealed that the global total emission from RPF’s is 2-3 orders of
magnitude higher than the respective emissions related to maintenance of all nuclear power
plants (NPP).
Given that situation we have seen in 2008 two peculiar hemisphere-specific
situations:
1) In the northern hemisphere, a joint shutdown of the global largest four
radiopharmaceutical facilities revealed the contribution of the normally ‘masked’ NPP related
emissions.
Due to an incident, the Molybdenum production at the “Institut des Radioéléments”
(IRE) in Fleurus, Belgium, was shut down between Monday 25 August and 2 December
2008. IRE is the third largest global producer of medical isotopes. In the same period, but for
different reasons, the other three worldwide largest producers (CRL in Canada, HFR in
The Netherlands and NTP in South Africa) also had scheduled and unscheduled
shutdowns.
The activity concentrations of 133Xe measured at the Schauinsland Mountain station near
Freiburg in Germany (situated 380 km SW of Fleurus) which have a mean of 4.8 mBq/m3 for
the period February 2004 – August 2008, went down to 0.87 mBq/m3 for the period
September – November 2008.
2) In the southern hemisphere, after a long break, the only radiopharmaceutical facility in
Australia started up test production in late November 2008.
In the period before the start-up, the background of radioxenon in Australia (Melbourne
and Darwin) was below measurable quantities. During six test runs of the renewed RPF at
ANSTO in Lucas Heights, up to 6 mBq/m3 of 133Xe were measured in the station at
Melbourne, 700 km SW from the facility.
This paper confirms the hypothesis that radiopharmaceutical production facilities are the
major emitters of radioxenon first of all. Moreover it demonstrates how the temporal shut
down of these facilities indicates the scale of their contribution to the European radioxenon
background, which decreased 6 fold. Finally we have studied the contribution of the start-up
of a renewed RFP to the buildup of a radioxenon background across Australia and the
southern hemisphere.
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 participating
institutions. |
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