Behaviour of nuclear contamination in urban areas

The Chernobyl accident on April 26th 1986 clearly demonstrated that radioactive material released from an accident at a nuclear power plant may deposit over a very large area and affect large populations.

In the early phase following the deposition, typical contamination patterns were recorded in different parts of Europe in the absence or presence of precipitation. However, these contamination patterns have changed with time, due to wind, frost, precipitation and human and animal activities (usually termed 'weathering'). The Contamination Physics Group has followed in detail the changes in the contamination levels on typical surfaces in urban, suburban and industrial environments. An example of this are the results of 7 measurement campaigns to the town of Gävle in Sweden, where the contamination levels from the Chernobyl release were sufficiently high to permit a monitoring with lead shielded germanium detector spectrometers.

Field expeditions have also been made to the heavily contaminated areas in Russia, Belarus and the Ukraine, where preliminary conclusions regarding the differences between wet and dry deposition were confirmed in the laboratory the specific retention capacities in common construction materials of the most important radioisotopes were established and a new method for determination of caesium specific sites, using gas chromatography on temperature programmed ammonia das desorption has been suggested by the Risø Group in collaboration with Harwell Laboratory, UK. The many field measurements made both by the Contamination Physics Group and by other laboratories have been applied in the URGENT model to describe in detail the different systems of migration processes of radioactive matter, which can be expected in an urban complex. The URGENT model, which was developed in the Group, can at present be applied to estimate the time-integrated external doses to inhabitants in urban or suburban housing environments.

Contact

Kasper Grann Andersson
Senior Scientist
DTU Nutech
+45 46 77 41 73