Reactor ruins: Federal agency maps radioactivity around Chernobyl

reactor ruins
Federal agency maps radioactivity around Chernobyl

For the first time in more than 30 years, experts from Germany and Ukraine have mapped the radioactivity in the exclusion zone around the Chernobyl reactor ruins.

The Federal Office for Radiation Protection (BfS) in Salzgitter published the first results in two overview maps – shortly before the 36th anniversary of the reactor catastrophe on April 26, 1986. Experts from the Federal Office and the State Agency of Ukraine for the administration of the exclusion zone had the radiation for the maps the wrecked Soviet nuclear power plant last September before Russia’s war against Ukraine.

The new maps are more up-to-date and have a better spatial resolution than the last representations from the 1990s, the authority said. Accordingly, the updated data confirm the previous findings from the years after the accident. Radioactive substances from the reactor spread primarily to the north and west.

Measurements at almost 200 points

For the comprehensive data collection, the scientists carried out aerial measurements from helicopters together with the Federal Police. In addition, measurements were made on the ground at almost 200 points and samples were taken from the ground, since the radioactive substances are deposited in the ground. The researchers measured the so-called local gamma dose rate. This indicates how much external radiation affects a person. According to the Federal Office, the radiation is mainly due to cesium-137 with a half-life of 30 years. Short-lived radioactive substances such as iodine-131 have not been detectable for years.

The new measurements showed that the local gamma dose rate in the exclusion zone is between 0.06 and about 100 microsieverts per hour, depending on the location. For comparison: According to the authorities, the natural local dose rate in Germany is between 0.06 and 0.2. People who were permanently outdoors in the exclusion zone in the places with the highest values ​​would have reached a radiation dose of 20,000 microsieverts after about eight days – the highest dose that people in Germany are allowed to receive in a year if they are exposed to radioactive radiation at work are exposed.

Again and again forest fires

The new data can be used to calculate how long people can stay in the exclusion zone without being exposed to unacceptable levels of radiation. This is important for the fire brigade, for example, who repeatedly have to put out forest fires there, the radiation protection experts said. Clean-up work and the disposal of ammunition after the war could also be supported in this way.

In the course of the invasion of Ukraine, the exclusion zone around Chernobyl came under Russian control. At the end of March, the Russian units withdrew and handed control back to Ukrainian personnel. Reports soon followed that Russian soldiers may have received radiation damage in the area.

dpa