Radioactivity Monitoring In Surroundings Of The Coal - Fired Power Plant Tuzla, Bosnia And Herzegovina

In this paper the influence of 12-year operation of coal power plant (CPP) Tuzla on radioactive contamination of soil in its vicinity was investigated. Coal, ash, slag and soil inside of CPP as well as soil were sampled for analysis during 12 years period, twice a year. Sampling of soil in expected zone of influence was performed at points 5 km before and after CPP along the dominating wind direction. Mean values of specific activities in samples of coal used in CPP Tuzla were 23.41 Bq kg-1 for 238U, 11.51 Bq/kg for 232Th, 17.03 Bq kg-1 for 226Ra and 94.72 Bq/kg for 40K, and they showed no indication on increase of observed radionuclides in coal. Mean values of specific activities in samples of ash for 238U, 232Th, 226Ra and 40K were 65.24, 37.59, 61.36 and 313.96 Bq/kg, respectively, and 47.32, 27.33, 38.11 and 237.15 Bq/kg, respectively, in samples of slag. Values of observed radionuclides in samples of soil inside CPP as well as on the point at 5 km before CPP in dominating wind direction were lower than those measured 5 km after CPP. On the base of obtained results we concluded that this was caused by the deposition of ash along the dominant wind direction. Ratios of specific activities after and before CPP for observed radionuclides in soil were 1.66 for 238U, 1.54 for 232Th, 1.52 for 226Ra and 1.43 for 40K. Mean value of this ratios was 1.54 with standard deviation of 0.09. Given ratios showed that dominant wind direction was probably the main cause of recorded increase of specific activities in soil after CPP Tuzla. Deposition of flying ash cause no significant increase of natural radioactivity in soil mainly because of low average activities of this radionuclides in coal. (author).