Distribution of natural radioactive isotope concentrations and emanation factors measured on concrete and brick samples produced in Hungary

Natural radioactive isotope concentrations and emanation factors were measured on concrete and brick samples produced in different parts of Hungary. The natural activity parameters measured on samples produced in a given factory within a period of 1 to 2 years show normal distribution. Samples received at different times from all the building factories under investigation showed about half normal and half lognormal distributions of natural activity parameters. Calculating with the arithmetical means obtained for each of the natural activities substituted into simple models, it was found that the radon and thoron activity is expected to increase by about 25% and the exposure from external radiation to decrease by a factor of 2.3 in the new prefabricated apartments made of concrete as compared with the conventional apartments with brick walls and concrete ceilings. The data obtained from the measurements were used to establish reference levels for the radiological grading of concrete and brick produced in Hungary