Regional distribution of natural and man-made radioactivity in Slovenia

Abstract

The regional distribution on of dose-rate as determined by the ionization cell and some data from uranium prospection were almost the only information about the variation of natural radioactivity over the territory of Slovenia (NW Yugoslavia) before the Chernobyl accident in 1986. Detailed specific studies were limited to the regularly monitored surroundings of the Krško Nuclear Power Plant (NPP), the uranium mine at Žirovski vrh and the research reactor near Ljubljana. Chernobyl radioactive fallout in 1986 was determined at specific sites by gamma-spectrometry of soil, grass and rainwater, but measurements of the regional distribution of fallout in 1986 were affected by different sampling techniques. During subsequent years measurements of soil samples and dose-rate were performed yearly at more than 60 locations selected by geographical, petrological and geological criteria. In the last 2 years field gamma-spectrometry and TLD dosimetry was introduced. The number of locations will be extended during the next few years. The data presented are compared with meteorological models and provide a basis for measurements of transfer factors.