Monitoring Radioactive Aerosols in the Object "Cover"

The results of an investigation of aerosols in the rooms of the object "Cover" at the Chernobyl nuclear power plant in November-December 2000 are presented. Using packets of Petryanov three-layer filtering materials, the dynamics of the volume activity of the products of the accident in the No. 4 unit and the daughter products of radon and thoron is traced, and the size of the carrier particles in room 207/5 is determined. It is shown that the ^sup 137^Cs concentration varied from 0.2 to 20 Bq/m^sup 3^. The median aerodynamic diameter of carrier particles ranged from 0.5 to 6 μm for ^sup 137^Cs and from 0.08 to 0.8 μm for the daughter products of radon. The sources of the coarsely dispersed cesium aerosols at maximum concentration were determined in both cases.[PUBLICATION ABSTRACT]