The radioecological risk of decommissioning of nuclear submarines. Possible accidents and normal conditions

In the report the results of the estimations of radiological risk of various stages of decommissioning of nuclear submarines are presented. At occurrence on nuclear submarine the heavy failure, relating to the class hypotetical volume of acting of radionuclides in atmosphere can reach 1.6E(15) Bq. Results of estimations probable doses on an axis of a trace of a radioactive loop show, that at distribution of radionuclides during atmospheric carry to 'agreed' settlement (500-1000 m) the maximum doses on its territory can make: about 6.0E(-3) Sv (for the whole body); 3.0E(-3) Gy for the leather (basal layer); 6.3E(-2) Gy for the lungs (acute exposure) and up to 1.8 Gy for the thyroid gland. Hypotetical failure for the estimation of the greatest possible radioecological consequences for hydrobiocenosis is considering, connected with single discharge of liquid radioactive waste (LRW) in water area. At navigating failure of the tanker with LRW in water area can arrive 300 M3 of LRW with the high contents of radionuclides (up to E(14) Bq). In account was accepted, that the receipt occurs during 30 days. At similar failure 1% of the area of a bay can be polluted above (3-4)E(4) Bq/l during the first days. The analysis of data on probable doses of exposure of hydrobionts has shown, that the maximum sizes of doses external exposure will be formed in near future after failure (1,4E(-4) Gy/day-1 day; 1,5E(-5) Gy/day-30 days) and correspond to dynamics of the contents radionuclides in sea environment. The capacity of a dose internal exposure on 1st year after failure does not exceed 4E(-6) Gy/day. Accounts show, that to the end 1st year after failure the specific activity a fish, living in region of probable pollution, for the given group radionuclides can make 4E(-1) ...3E(3) Bq/kg. Consumption of a similar fish in quantity 1 kg can result to additional exposure of critical group of the population in doses up to 2E(-5) Sv. Accordingly, the additional size of radiating risk at the expense of the given influence will not exceed E(-6) year-1. Situation with the formation of a constant stain of pollution of sea bottom owing to constant organized discharge of insignificant amounts radionuclides with products of corrosion from temporary storage of reactor compartments of decommissioned nuclear submarines is considered also. Initial data for account of concentration of radionuclide in a ground were the maximum concentration of products of corrosion in a ground 10 Bq/dm2 (6,64 Bq/kg). According to accounts, the total effective dose for critical group of the population at the expense of consumption a fish, caught in region of items long-duration storage, will not exceed E(-8) Sv. The maximum expected capacity of a dose for bentic hydrobionts (weighed in is thicker than marine plankton) will not exceed E(-2) Gy/day. Comparison of sizes of control concentration in water and ground, allowable volumetric activity of drainage waters and settlement sizes of the contents of radionuclides in drainage water disposal have allowed to make a conclusion that the examined conditions of functioning of the temporary storages of reactor compartments cannot resul in excess of radiologic capacity of water area. (author)