ОЦЕНКА РАДИАЦИОННОЙ ОБСТАНОВКИ В РАЙОНЕ ПРОВЕДЕНИЯ МИРНОГО ЯДЕРНОГО ВЗРЫВА «ТАХТА-КУГУЛЬТА»

Abstract

Purpose: Radiation survey in the area of peaceful nuclear explosion «Takhta-Kagylta» in the Stavropol Region.
 Material and methods: Radiation survey was performed on the territory of the protected area and on the territory of the 30-km zone from the explosion site. Methods of pedestrian gamma survey with a portable spectrometric complex Multirad-M were used in the course of the survey, along with gamma spectrometric and radiochemical measurements of radionuclide activities in samples and radiochemical separation of 90Sr and 137Cs. The measurement of tritium activity concentration in water was carried out using a low-background liquid alpha-beta radiometer Quantulus-1220.
 Results: The highest average value of gamma ambient dose equivalent rate was obtained in the area of the peaceful nuclear explosion site. A value of ambient dose equivalent rate at the area between the site and Kevsala village is lower than on the site, but higher than in Kevsala village and in other settlements. The mean value of the surface contamination of soil with 137Cs on the site was 0.43 kBq/m2, while that of 90Sr was 0.055 kBq/m2. Average values of soil surface contamination with radionuclides in the settlements located in the area of the explosion vary over the range between 0.16 and 0.37 kBq/m2 for 137Cs and between 0.035 and 0.066 kBq/m2 for 90Sr. 241Am specific activity values were below the minimum detectable activity (0.01 – 0.04 kBq/m2 at the time of the soil sample measurement of 10–30 h).
 The contents of 3H, 90Sr and 137Cs radionuclides in drinking water and water of the surface water reservoirs is significantly lower than the intervention levels established in NRB-99/2009. 
 Conclusions: Radiation situation at the location of the technological well complies with the requirements of SanPiN 2.6.1.2819-10 “Radiation Safety and Protection of the Population Living in the Areas of Peaceful Nuclear Explosions (1965 – 1988)”, and does not pose a threat to the health of the population when staying there. It is necessary to arrange the territory of the protection area and technological (charging) well in accordance with the requirements of SanPiN 2.6.1.2819–10.
 Within the framework of long-term radiation monitoring, it is necessary to provide for the monitoring of the tritium content in the produced gas and in the groundwater of the Krasnogvardeiskoe deposit (located in the direction of the spread of groundwater from the location of the peaceful nuclear explosion).