Kinetics of dissolution of Chernobyl fuel particles in soil in natural conditions

Kinetic of fuel particles dissolution under natural environmental conditions has been investigated using the data on 90Sr speciation in soils collected from 1995 to 1997 within the Chernobyl nuclear power plant 50 km zone. The dependency of fuel particles dissolution constants on the soil acidity (pH=4–7) has been obtained on the basis of large and statistically reliable experimental data. Results show that between 2 and 21% of 90Sr activity is associated with weathering resistant fuel particles. Therefore, these particles would not influence the radiological situation in the near future. The map of the main agrochemical characteristics and the map of the fuel particles dissolution constants have been created for the 30-km zone territory. According to the prognosis of dynamics of fuel particles dissolution in the investigated zone, a radiological situation along the fuel paths of radioactive fallout in present time reached a stable state. An increasing in absolute contents of 90Sr mobile forms in neutral soils will be observed in the next 10–20 yr. However, the difference between the maximum level of mobile forms contents and their existing contents will not exceed 20%.