Modeling of atmospheric transfer of radionuclides in the form of water aerosols from the surface area of water bodies using the example of Lake Karachay, Russia.

Based on the analysis of multi-year monitoring data on atmospheric air contamination in the vicinity of Lake Karachay, Reservoir V-9, a model is suggested here for carry-over of radionuclides (trace elements) in the form of water aerosols from the reservoir surface area. The concept of fractionation (accumulation) coefficients is introduced for different radionuclides present in V-9 Reservoir water aerosols as compared to the reference radionuclide 137Cs. The range of possible fractionation coefficient values is estimated for 134Cs, 90Sr, 103,106Ru, 95Zr+ 95Nb, 125Sb, 144Ce and Pu radionuclides. It is shown that, for a numerical assessment of radioactive pollution of the atmosphere with water aerosols, it is convenient to express the capacity of the source of releases as a product of three factors: (1) the activity concentration in the reservoir water, (2) the effective rate of generation of water aerosol volume from the reservoir surface area (~ 20 cm3 m-2 year-1 in relation to the reference radionuclide 137Cs), and (3) the fractionation coefficient of the radionuclide under consideration in water aerosols as compared to the reference nuclide. It is proposed here to model transfer and dispersion of water aerosols in the atmosphere using the standard Gaussian model, and it is shown that this allows estimation of atmospheric pollution in the vicinity of the reservoir with acceptable accuracy.

Experience and the results of emergency management of the 1957 accident at the Mayak Production Association.

The experience accumulated while dealing with the aftermath of a major nuclear accident (the 'Kyshtym Accident') in 1957 at the Mayak complex in the Southern Urals of Russia is summarised. Information is presented on the causes of the accident, on the radiation environment and radioactive contamination of the affected territory in the critical period, and on the system of emergency management and decision-making adopted when dealing with the accident and its aftermath. The technical and organisational approaches applied and methods used are described, as well as remediation results and the current situation 60 years after the accident. It is demonstrated that the implementation of fairly simple and self-evident organisational and technical solutions gave good results, and that appropriate timely and task-oriented measures were applied. Safety relevant conclusions and recommendations are presented.

Characterization of biocenoses in the storage reservoirs of liquid radioactive wastes of Mayak PA. Initial descriptive report.

As a result of operation of the Mayak Production Association (Mayak PA), Chelyabinsk Oblast, Russia, an enterprise for production and separation of weapon-grade plutonium in the Soviet Union, ecosystems of a number of water bodies have been radioactively contaminated. The article presents information about the current state of ecosystems of 6 special industrial storage reservoirs of liquid radioactive waste from Mayak PA: reservoirs R-3, R-4, R-9, R-10, R-11 and R-17. At present the excess of the radionuclide content in the water of the studied reservoirs and comparison reservoirs (Shershnyovskoye and Beloyarskoye reservoirs) is 9 orders of magnitude for (90)Sr and (137)Cs, and 6 orders of magnitude for alpha-emitting radionuclides. According to the level of radioactive contamination, the reservoirs of the Mayak PA could be arranged in the ascending order as follows: R-11, R-10, R-4, R-3, R-17 and R-9. In 2007-2012 research of the status of the biocenoses of these reservoirs in terms of phytoplankton, zooplankton, bacterioplankton, zoobenthos, aquatic plants, ichthyofauna, avifauna parameters was performed. The conducted studies revealed decrease in species diversity in reservoirs with the highest levels of radioactive and chemical contamination. This article is an initial descriptive report on the status of the biocenoses of radioactively contaminated reservoirs of the Mayak PA, and is the first article in a series of publications devoted to the studies of the reaction of biocenoses of the fresh-water reservoirs of the Mayak PA to a combination of natural and man-made factors, including chronic radiation exposure.