International measuring exercise 2015 in Germany

In June 2015, BfS and the Federal Police invited five European measuring teams to take part in a cross-border campaign for helicopter-borne measurements in the area of Saxony/Thuringia/Czech Republic. A number of measuring tasks had to be performed in order to optimise the interaction of different measuring teams and systems during the helicopter-borne determination of radiological soil contamination.

Measuring areas at a glance Source: www.openstreetmap.org

This type of exercise is an essential element of emergency response in the participating countries, in particular in areas along the borders, since seamless cooperation without long preparation times is key in the event of an incident.

The measuring teams from Switzerland, France, the Czech Republic and Germany had seven measuring areas available for the different exercises, shown as areas A to G on the map. The selected measuring areas also included former Uranium mining sites (contaminated WISMUT sites). Depending on the progress of the redevelopment work, it can still be observed today that the Gamma dose rate is higher at these sites than in the surrounding areas. The increase is due to radioactive residues from the former Uranium production. This fact makes it interesting from a radiological point of view to investigate these areas and makes it possible to compare the measuring results obtained by different teams over a relatively large range of values.

The following tasks were performed:

• Measurements over a reference area in order to compare the measuring results obtained by the individual teams (area A),
• Simultaneous, collective operation of all the teams in order to map a rather large area (area B / B1 to B6),
• Development of a common measuring strategy and coordination of two teams per measuring area (areas D, E, F),
• Search for radioactive sources (area C),
• Optional task: Underground measurements over a lake (area G).

Spatial distribution of the gamma dose rate Source: Kartendaten: www.openstreetmap.org, www.viewfinderpanoramas.org

The BfS section "Decision-Support Systems, Evaluation of Radiological Situation and Communication" supported the teams so that they were able to create a map showing the spatial distribution of the Gamma dose rate for the entire measuring area (see Figure) on the same day when they had performed the measuring flights over areas B1 to B6.

Three radiological anomalies were identified, two in area B4 and one in area B6. The two anomalies in area B4 are due to the former Uranium mining at Johanngeorgenstadt and in the Northern part of the Czech Republic. The anomaly in area B6 was caused by material testing activities using an iridium source.