Measurements of radioactivity in plant and soil samples taken near a nuclear power plant

Abstract: This project is a study of six soil and vegetation samples taken near the nuclear power plant at Ringhals, Sweden. The purpose was to detect any signs of radioactivity in the soil and vegetation originating from the plant, while simultaneously giving insight on the advantages and limitations of using equipment from the radioecology lab at the Swedish University of Agricultural Sciences. The samples were examined by a high purity germanium detector, and the resulting spectra were analyzed in Matlab. Besides Cs-137 from the Chernobyl accident and from atomic bomb tests the study found no proof of radioactivity derived from nuclear power waste or emissions. The results from the analysis were compared with the automatic software Apex-Gamma. In general there was a good agreement between the two methods, with discrepancies never larger than a factor of two. An improvement of the accuracy can be obtained through longer measurement times, and analysis of each spectra separately before the subtraction of the background contribution.