GEOGRAPHICAL MAPPING AND ASSOCIATED FRACTAL ANALYSIS OF THE LONG-LIVED CHERNOBYL FALLOUT ISOTOPES IN GREECE

Right after the Chernobyl accident, a soil sampling programme has been undertaken by the Nuclear Engineering Section of the National Technical University of Athens in order to detect and quantitatively analyse the long-lived isotopes in the Chernobyl fallout. 1242 soil samples of 1cm thick surface soil were collected over Greece during the period May - November 1986. The samples were counted and analysed using Ge detector setups. The Cs-137 fallout data have already been graphically presented; this analysis led to the mapping of Cs-137 deposition in the form of a four-class histogram, extending between 0-150 kBqm??. In an attempt to improve this analysis and also to extend it to other isotopes in the fallout an in-house built Unix-based Data Base/Geographical Information System (DBGIS) was developed. Multifractal analyses of the deposition patterns have also been performed by the use of relevant methods. In the present work, the deposition of Cs-137, Cs-134, Ce-144, Ce-141, Sb-125, Ag-110m, Ru-106, Ru-103, Zr-95 and Mn-54 in the form of contour histograms is presented and the results of the associated fractal analysis is communicated. The maximum detected values of the above mentioned isotopes are 149.5±0.1, 76.1±0.1, 32.9±0.2, 46±2, 4.56±0.02, 7.98±0.02, 79.1±0.4, 337±2, 20.1±0.2 and 3.02±0.02 kBqm?? respectively. Furthermore, a statistical technique to compare contour mappings is introduced and applied to explain the differences in the mappings of the above isotopes.