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Ten years of EURADOS intercomparisons of European early-warning systems


Since the nuclear reactor accident of Chernobyl in 1986, nation-wide measurement networks for the determination of the area dose rate of external gamma radiation have been established in almost all member states of the EU. The early detection of nuclear accidents and the assessment of their possible radiological consequences are decisive prerequisites for an adequate action of the state. Europe-wide, in all national early-warning systems taken together, more than 4000 stations are in use for the measurement of the area dose rate. In the case of a radiological emergency, their measurement values must be transmitted to the EU commission at least hourly. To obtain measurement results which are comparable across national borders, there is - more than 20 years "after Chernobyl" - still a clear demand for a harmonization of the measurement and assessment methods of the European early-warning systems.

For more than ten years, the EURADOS Working Group "Environmental Radiation Monitoring" has been dealing with the metrological aspects of the measurement of the area dose rate by means of early-warning systems. In five intercomparisons, performed between 1999 and 2009, approx. 70 measuring systems of 18 European member states have been investigated and calibrated. Thereby, PTB’s world-wide unique combination of reference sites for environmental dosimetry has been of central importance. These reference sites allow, among other things, the response of detectors for cosmic and terrestrial radiation to be selectively determined, their inherent backgrounds to be determined, the energy and dose rate dependence to be measured, and dosimetry systems to be calibrated at low dose rates with traceability to the primary standards.

The knowledge gained in, and the conclusions drawn from the above-mentioned European comparisons performed at PTB’s reference sites for environmental dosimetry are indispensable prerequisites for the harmonisation of the ambient dose rate measurements for environmental monitoring in Europe.