CHARACTER OF RADIOACTIVE CONTAMINATION FOR MAIN OBJECTS AND ENVIRONMENT AT SNTS (AIR BASIN)

Radioactive contamination of air basin at the Test Site is stipulated by presence of large-scale surface sources of contamination: testing grounds Opytnoye Pole, Balapan, CRS and traces from radioactive fallout from tests in atmosphere.
Analysis of characteristics and peculiarities of the processes for natural and artificial dust formation showed that considerable contamination of near-surface atmosphere with radioactivity is only possible at man-caused dusting (motion of trucks and other works associated with dust lifting up) and at fire in steppe.
Based on the investigations and model calculations there were assessed internal irradiation doses for population due to inhalation intake of artificial radionuclides; this, in turn, was used in assessment of radiation risks.
Based on obtained results one can make conclusion that radioactive pollution of atmosphere can be dangerous for a person only directly at radiation-hazardous spots at the Test Site and only in case when large amounts of dust are lifted up in air at that moment (at dust storms, man-caused dusting, etc.) So, studies of artificial radionuclides in vicinity of the testing ground Opytnoye Pole revealed considerable exceeding over regulatory limits. This means that presence and, particularly, activities resulted in dusting in vicinity of such sites is dangerously. Nevertheless, transboundary transfer of radioactivity outside these places and outside the SNTS perimeter is negligible and represents no hazard. Outside the Site perimeter, volume activity of artificial radionuclides is considerably, for orders of magnitude, below regulatory limits. So, for instance, in v. Sarzhal and Kurchatov city, 239+240Pu volume activity is for 352 and 25 000 times below the acceptable one, respectively (but it still remains much higher that concentrations of these radionuclides in air of cities located far from the Site.

Radionuclide

Sampling location

Volume activity, nBq/m3

Year of sampling

239+240Pu

Near Opytnoye Pole

14 000 000

2001

137Cs

Near Opytnoye Pole

800 000

2001

239+240Pu

v. Sarzhal

7100

2000-2001

239+240Pu

city of Kurchatov

100

2000-2001

137Cs

city of Kurchatov

4 000

2000-2001

137Cs

city of Almaty

200

1995

239+240Pu

city of Astana

29

2001

239+240Pu

city of Munich

2-6

1987-1991

NRB-99: 137Cs – 27 Bq/m3, 239+240Pu – 2,5*10-3 Bq/m3