After the Chernobyl nuclear accident in April 1986, large areas of Ukraine, Belarus and the Russian Federation were exposed to radioactive contamination, the main contaminants being the long-lived radionuclides caesium-137, strontium-90 and plutonium-239. In the most contaminated regions (Kiev, Zhitomir, Rovmo, Gomel, Mogilev and Bryansk regions), there are forests consisting of young and middle-aged pine and pine hardwood stands very sensitive to fire (because these forests are not thinned). In the year of the Chernobyl accident, a total of 1775 fires burned 2336 ha of forests in these regions. Fires in radioactively contaminated forests constitute a grave problem due mainly to the way in which they mobilise radioactivity into the air. Research shows that in 1990 the bulk of caesium-137 was concentrated in the forest litter and upper mineral layers of the soil. By 1992, vertical migration of radionuclides caused an increasing contamination of the upper soil layer so that, at present, surface fires (fires in contaminated litter and humus) and ground fires in contaminated peat pose a serious danger. Furthermore, incomplete combustion causes open sources of ionising radiation: in the zones where the density of radiocaesium contamination of the soil is 0.6 to 1.5 TBq per km2 (TBq=1012 TBq) and higher, the specific radioactivity of ash and partly burned litter has been measured in the range of 180 to 1086 kBq per kg. The level of radioactive caesium in aerosols after a fire increases to ten times the level before the fire. Another great danger is posed by high-intensity (crowning) fires which develop convective activity and lift radionuclides into the atmosphere. To obtain accurate quantitative assessment of the behaviour of radionuclides during forest fires, laboratory and field experiments are necessary. These experiments are needed to develop fire behaviour models, especially for heat and mass transfer in the near-ground layer. In addition, the contaminated forest environment has affected the working conditions of forest fire fighters and heavily contaminated fire-fighting equipment. Source: Dusha-Gudym, 1992
Another great danger is posed by high-intensity (crowning) fires which develop convective activity and lift radionuclides into the atmosphere. To obtain accurate quantitative assessment of the behaviour of radionuclides during forest fires, laboratory and field experiments are necessary. These experiments are needed to develop fire behaviour models, especially for heat and mass transfer in the near-ground layer. In addition, the contaminated forest environment has affected the working conditions of forest fire fighters and heavily contaminated fire-fighting equipment. Source: Dusha-Gudym, 1992
Source: Dusha-Gudym, 1992