Experts from BfS and the Federal Police exercised the measurement of radioactivity from helicopters in Mecklenburg-Vorpommern from 5 to 9 November 2018.

From 5 to 9 November 2018, experts from the BfS and the Federal Police practised taking measurements of radioactivity from a helicopter in Mecklenburg-Vorpommern.

Measurements were taken above the premises of EWN Entsorgungswerk für Nuklearanlagen GmbH and over an area of some 500 square kilometres between Demmin, Anklam and Neubrandenburg.

The measurements did not lead to the identification of any conspicuous values in the measuring areas. Artificial radioactive substances (cobalt-60 and iridium-192) were only detected in two smaller areas near Lubmin. In both cases, this radiation originated from an authorised use of radioactive substances that is subject to corresponding official safety measures.

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Helicopter measuring excercises

In a joint training exercise on 29 November 2018 in Oranienburg (Brandenburg), experts from the Federal Office for Radiation Protection (BfS) and the Federal Police measured the radioactivity of the soil from a helicopter.

In a joint training exercise on 29 November 2018 in Oranienburg (Brandenburg), experts from the Federal Office for Radiation Protection (BfS) and the Federal Police measured the radioactivity of the soil from a helicopter.

The exercise showed that airborne gamma spectrometry can quickly provide a rough overview of the radiological situation in an area. Within three flight hours, the measuring team mapped about 24 square kilometer and identified radiological anomalies in two areas.

Exercise area Oranienburg

Until the end of the Second World War, two plants (the Auer- and Goetschke-Werke) were located in Oranienburg. In these plants, naturally occurring radioactive materials were processed for production and research purposes. Large-scale bombardments of Oranienburg in March 1945 and the destruction of the production facilities caused residues of the radioactive materials to enter the surroundings. They can be detected by measuring gamma radiation.

Measurements by the Brandenburger Landesamt für Arbeitsschutz, Verbraucherschutz und Gesundheit (Brandenburg State Office for Occupational Safety, Health and Consumer Protection) of the local gamma dose rate on radiologically relevant areas of the two companies since 1991 show that the local gamma dose rate here is significantly higher than is usual for this region. Since the 1990s, the authorities in Brandenburg have been assessing the radiologically relevant areas from a radiological point of view and initiating appropriate remediation measures.

Using a measuring system mounted to the helicopter, the Federal Office for Radiation Protection in Oranienburg had mapped the environmental radioactivity in July 1997 and localised four areas with increased radioactivity. Of those four areas with increased radioactivity, increased radioactivity was measured 2018 in only two. The ambient gamma dose rate assessable from the helicopter is only slightly higher than the average ambient gamma dose rate in Germany. The remediation measures taken by the Brandenburg authorities are thus having an effect.

Measurements from the air and on the ground can lead to different results.

How do measurement results from the ground and from the air differ?

The measured values of the Brandenburg authorities from the ground and the measured values of the Federal Office for Radiation Protection from the air must be interpreted differently: when measuring from a height of almost 100 m, the area that contributes to the measurement result is significantly larger than when measuring on the ground.

The spatial resolution of the helicopter-borne measurements is thus lower, and very small-scale contaminations, which could be detected by means of targeted measurements on the ground, cannot be mapped.

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Helicopter measuring excercises

Representation of the results from the measurement flights (ambient gamma dose rate ODL, in nanosieverts per hour)

The BfS and the Federal Police practised determining radioactive substances deposited on the ground in a helicopter-borne gamma spectrometry measurement exercise from 20 to 22 September 2016 near Bayreuth.

The region around Bayreuth provides particularly good conditions for training flights due to natural uranium and thorium deposits that are detectable from the air. Moreover, the region provides the opportunity to investigate whether the caesium-137 deposited there 30 years ago after the Chornobyl (Russian: Chernobyl) reactor accident can be still detected today from the helicopter.

The ambient dose rates (ODL) calculated from the current measurements are mostly within the range of the levels typically occurring in Germany, that is about 100 to 200 nanosieverts per hour. One single local increase of 320 nanosieverts per hour was determined in a quarry located west of Tröstau-Leupoldsdorf. This increase is due to potassium- and uranium-containing minerals exposed in the quarry. Radiation anomalies identified in radiological surveys during the period from the 1950s to 1970s were confirmed by the airborne gamma spectrometry surveys conducted in 2016.

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Helicopter measuring excercises

Helicopter used in the measurement

In a airborne gamma spectrometry measurement exercise jointly conducted by the Federal Office for Radiation Protection (BfS) and the German Federal Police (Bundespolizei / BPOL) from 6 to 9 October in Saxony and Thuringia, areas near Zwickau, Lengenfeld, Schneeberg, Freital, Johanngeorgenstadt, and Seelingstädt were overflown.

For most of these areas, radiological data had been mapped during previous measurement exercises, for example by measurements near Lengenfeld and Freital already in 2003, and near Zwickau, Johanngeorgenstadt und Seelingstädt in 2003 and 2010. In addition, the premises of the research site Rossendorf were selected for measurements in 2014.

Special features of measured areas

Survey area in Johanngeorgenstadt (Wismut sites)

There are uranium mining residues and legacies in all measured areas, except for Rossendorf. The sites owned by the Wismut GmbH were, or are being, remediated on the responsibility of the Wismut GmbH. So-called former Wismut sites, which are not owned by the Wismut GmbH any more, are being restored within the scope of an agreement between the Federal and State Governments in Saxony.

Above the uranium mining residues and legacy sites not remediated (mainly disposal sites and tailings ponds) there is evidence of increased ambient dose rates (ODL) compared to the environment. This is due to the naturally radioactive residues from uranium production. Above remediated areas, there is almost no increase in ambient dose rates.

In all measurement areas, the average ambient dose rate (ODL) was within the range of the natural radioactivity usual in Germany. Localised divergences are due to residues from uranium mining.

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Helicopter measuring excercises