Practising radioactivity measurements from the air

From 15 to 18 June, measurement experts from different countries will use helicopters to determine the radioactivity at ground level in parts of Saxony, Thuringia and the Czech Republic. These measurement flights are part of an international exercise hosted by the Federal Office for Radiation Protection (BfS) and the Flight Service of the German Federal Police (BPOLFLD), in close cooperation with the Czech Institute for Radiation Protection (SÚRO). Six measurement teams from four nations will take part:

• Státní ústav radiační ochrany, v.v.i. – SÚRO (Czech Republic)
• Commissariat à l’énergie atomique – CEA (France)
• Institut de radioprotection et de sûreté nucléaire – ISNR (France)
• Nationale Alarmzentrale – NAZ (Switzerland)
• Bundesamt für Strahlenschutz – BfS, Bundespolizei-Flugdienst – BPOLFLD (Germany, two joint teams)

The use of helicopters and sensitive measuring devices makes it possible to identify radioactive substances on the ground rapidly and over large areas – without the need to enter these areas on ground level. This ability can be of utmost importance for quickly obtaining an overview of the radiation exposure on the ground, in particular in the event of an accident at a nuclear power plant with release of radioactive substances. In such event the competent authorities need reliable measuring data in order to decide which measures need to be taken for the protection of the population.

The exercise is focused on transnational cooperation and coordination: Radioactivity does not stop at borders and nuclear power plants are frequently situated in the immediate vicinity of national borders. The participants will exchange knowledge about their particular national approaches and will be given specific tasks to complete. This will give them the chance to practise the coordination and performance of joint measurements so that neighbouring states would be able to support each other and cooperate efficiently in the event of accidents, including in frontier areas. The tasks include:

• Comparative measurements over the same area,
• Joint radiological mapping of areas and
• The identification of radioactive substances that have been purposefully placed (i.e. source-tracking).

Measurement areas

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

In Thuringia, measurements will be performed around the municipalities of Seelingstädt and Ronneburg. In Saxony, the helicopters will fly over the Rossendorf research center, areas in the vicinity of Freital and Zwickau (Crossen district) and a larger area reaching from Reichenbach and Lößnitz (in the north) to the Czech Republic.

The flight level will be at least 90 metres in all areas. Flight times will be between 9 am and 5 pm. Police and military helicopters will be used as well as civil helicopters.

All measuring areas (except Rossendorf) have a legacy of pollution from uranium mining. Special measuring devices show an increased gamma local dose rate (ODL) in areas that have not yet been sanitized (in particular waste dumps and settling ponds), which is due to the natural radioactive residues from uranium production. Such an increased local dose rate is usually not found in sanitized areas.

Further BfS measurements on the ground

On 23 and 24 June the Federal Office for Radiation Protection (BfS) will perform another exercise in the same region: 13 measurement vehicles will be on the road around the municipalities of Seelingstädt, Aue, Lengenfeld and Mühlental in order to determine the radioactivity on the ground. This exercise is also part of the emergency training: If radioactive substances are released into the environment, radioactivity measurements performed on the ground and from the air can be complementary for the assessment of the situation. Since the measurement areas in both exercises overlap and the measurements are performed within a rather short interval, they will help to compare and optimise the different measurement procedures.