Use of the radiation environmental monitoring results for control of the atmospheric releases of iodine-131 by the facility

The analysis was performed, whether the following characteristics correspond with each other: data on the annual release of the radionuclide by the enterprise, the calculation model used for establishing the annual permissible release levels of radionuclides, and the annual average volume activity of the radionuclide, determined using the data of routine radiation monitoring of the surface air. Such analysis was carried out for the release of 131I from the L.Ya. Karpov Scientific Research Institute of Physics and Chemistry (Obninsk) in 2013–2022. It is shown that for the enterprise release in 2013–2022, the results of environmental radiation monitoring confirm both the data of radiation control of the ¹³¹I release source and the correctness of the radionuclide air transfer calculation model. The average annual meteorological dilution factor of the ¹³¹I for the enterprise release in the surface layer of the atmosphere, estimated from monitoring data, does not exceed the model calculated value. Strong correlation was revealed between the average annual volume activity of ¹³¹I in the surface air, obtained using measurement results, and data on annual air releases of the enterprise. No correlation was found for the variability of the dilution factor estimated by the transfer model and monitoring data. It may be caused by the heterogeneity of the ¹³¹I releases by the enterprise during the year.

1. IAEA Safety Standards. Environmental and Source Monitoring for Purposes of Radiation Protection. Safety Guide No. RSG-1.8. IAEA, Vienna; 2005. 119 p.

2. Vasyanovich ME, Ekidin AA, Vasilyev AV, Kryshev AI, Sazykina TG, Kosykh IV, et al. Determination of radionuclide composition of the Russian NPPs atmospheric releases and dose assessment to population. Journal of Environmental Radioactivity. 2019;208-209: 106006.

3. Ageeva NV, Kim VM, Vasilyeva KI, Katkova MN, Volokitin AA, Polyanskaya ON. Long-term observations of the content of 131I in the surface layer of the atmosphere of Obninsk, Kaluga region. Radiatsiya i risk = Radiation and Risk. 2015;24(1): 96107 (In Russian).

4. Masson O, Steinhauser G, Wershofen H, Mietelski JW, Fischer HW, Pourcelot L, et al. Potential Source Apportionment and Meteorological Conditions Involved in Airborne 131I Detections in January/February 2017 in Europe. Environmental Science & Technology. 2018. Vol. 52. P. 8488-8500. URL: https://pubs.acs.org/doi/10.1021/acs.est.8b01810.

5. Panchenko SV, Pripachkin DA, Kryshev AI, Katkova MN. The experience of using impurity scattering models in an urban environment. Atomnaya energiya = Atomic Energy. 2020;128(5): 282-288 (In Russian).

6. Buryakova AA, Bulgakov VG, Kryshev AI, Katkova MN. Radiodine, 131I, release into the atmosphere during normal operation of the radiopharmaceutical production facility at the Karpov Institute of Physical Chemistry: analysis of 131I concentration in the air and radiation dose to the population of the Obninsk city and its surroundings. Radiatsiya i risk = Radiation and Risk. 2021;30(3): 103-111. DOI:10.21870/0131-3878-2021-30-3-103-111 (In Russian).

7. Kryshev AI, Ivanov EA. Estimating the distribution of maximum values of the atmospheric dilution factor for radioactive discharges in the areas of nuclear power plants. Meteorologiya i gidrologiya = Russian Meteorology and Hydrology. 2022;9: 114-122. DOI:10.3103/S1068373922090102 (In Russian).

8. The radiation situation in Russia and neighboring countries in 2017. Yearbook. Obninsk: RPA «Typhoon», Roshydromet; 2018. 360 p.

9. The radiation situation in Russia and neighboring countries in 2021. Yearbook. Obninsk: RPA «Typhoon», Roshydromet; 2022. 342 p.

10. Kobzar AI. Applied mathematical statistics. for engineers and Scientists. Fizmatlit, Moscow; 2006. 816 p. (In Russian).