Monitoring of the radioactivity concentration of air in the area of the IFIN-HH, Romania

The paper presents the concept and the results obtained during an annual survey of the radioactivity concentrations in our Institute, a nuclear centre, involving research, production and use of radioisotopes, a nuclear reactor under decommissioning and a radioactive wastes treatment unit. The Department of Life and Environment Physics, in charge with the survey, established procedures for sampling , measurement and reporting results. Generally, for the air survey the sampling is based on the use of air filters. The measurements are carried out at determined time intervals chosen such as to cover the measurement of the short-lived natural radon daughters, as well as the monitoring of long lived natural and artificial radioisotopes. The measurements are performed by the following methods: (i) gross alpha and beta activity measurements at 3 minutes after collection, after 20 h, and after 5 days, by the use of a high sensitivity gross alpha-beta activity system; (ii) gross gamma activity after 5 days from sampling, by the use of a gamma measuring system. The results obtained are in good agreement with other methods. At the same time, the conclusion is that the main part of the measured radioactivity is due such as the measurements performed at various intervals showed to the radon short-lived daughters: lead and bismuth. The concentration of artificial radionuclides is within the same range as in other Romanian areas where no nuclear activities are effected. (authors)