Presence of technologically-enhanced naturally-occurring radioactive materials in the Czech Republic

NRI Rez participates in the TENORMHARM project within the 5th EU Framework Programme. NRI's effort is focused on evaluation of the NORM inventory and assessment of radiation dose and health risks to workers and members of the public. In the case of phosphate fertilizer production, three major factories provide for Czech consumption at present. Nowadays, generally less radioactive raw materials are used, such as yellow phosphorus, phosphoric acid, Kola apatite concentrate and AMOFOS. Only the Kola apatite concentrate contains higher quantities of 238U, 226Ra and 228Th (several tens of becquerels per kilogram), but even in this case the resulting annual effective dose received by workers does not exceed the regulatory limit. Titanium dioxide pigments are produced in only one factory. Ilmenite from Ukraine (approximately 140 Bq/kg 238U and 80 Bq/kg 228Th) is used as the raw material. The final product (rutile-TiO2) contains only negligible quantities of these radionuclides. The majority of the radioactivity content thus remains in the various wastes; for example, the concentrations of 210Pb and 226Ra are up to 1000 Bq/kg in sludges. Currently, one factory processes zirconium refractory material (EUCOR). Only zirconium-containing bricks (with a 226Ra activity concentration of approximately 1700 Bq/kg) discarded from glass factories are used for EUCOR production. The current consumption of approximately 200 t of zirconium input material (bricks) means reprocessing of 340 000 kBq of 226Ra. Coal exploitation and use represents one of the most important industries concerning NORM. The concentrations of uranium and thorium in Czech brown coal are 5-16.3 ppm and 0.2-30.2 ppm respectively; the hard coal contains 2-9 ppm uranium. The majority of the coal is used for energy production. The uranium and thorium concentrate mostly in the ash and slag (<12 ppm U and about 20 ppm Th); the concentration of all radionuclides in gypsum produced in the desulphurization process is negligible. The majority of oil and gas used in Czech industry is imported. Measurements of samples of oil sludge from cleaning of the IKL and Druzba pipelines and from oil tanks exhibited only negligible concentrations of all radionuclides (tenths of a becquerel per kilogram). A similar range of activity has been found in samples from domestic oil exploitation. Evaluation of radioactivity in sludges resulting from the 68 ground and surface water treatment installations was performed by NRPI. An average 226Ra activity concentration of 200 Bq/kg was identified in groundwater treatment sludges. (author)