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Serious concerns are provoked by ever more frequent cases of diseases and pathological changes 

 (including those to the cardiovascular system) noted in pinnipeds inhabiting the Barents-White 

 Sea ecosystem [27]. These changes cannot be unambiguously linked to LRW dumping, but the 

 theoretical possibility of such a link exists. 



At the same time, budget calculations of the share of total anthropogenic radiation contami- 

 nation of marine ecosystems due to LRW (2.5-5.0%) indicates with a fair degree of certainty that 

 the effect of discharged LRW on marine ecosystems cannot be a determining negative factor on 

 the scale of the northern and far eastern seas adjacent to Russian territory. 



The radiation hygienic and radioecological danger of SRW dumped at sea is determined by 

 their radionuclide content and activity, the condition of their protective barriers (degree of water 

 tightness of their packing containers, rate of the latter's corrosion, etc.). 



A comparative analysis of the potential danger of SRW dumped at sea from vessel and ship 

 nuclear power plants suggests the conclusion that the greatest threat in radiation hygienic and ra- 

 dioecological terms is presented by reactors with SNF in place in the Kara Sea. In cases when re- 

 actor compartments and reactors with damaged cores in place dumped at sea were specially pre- 

 pared with reinforced protective barriers (filling internal cavities with flirfijrol or cement, additio- 

 nal sealing, etc.), a substantial release of radionuclides in the near future seems unlikely. 



However, this theoretical conclusion may be incorrect, since the actual course of corrosion 

 processes and transformation of protective barriers erected is unknown. No full-scale experiments 

 of sufficient duration and similarity to actual conditions were performed during the development 

 of protective barriers and estimation of computed time to seal failure. And until each and every 

 dumped SRW with high activity levels is inspected, no final conclusions concerning them can be 

 drawn. 



The computed design time to possible seal failure for the block of the first nuclear power 

 plant of the icebreaker Lenin, which contains three reactors without nuclear fuel, is up to 500 

 years. No similar data for other sunken reactors were furnished to the Commission, and reevaluat- 

 ing all these calculations, if they exist, is an important objective for the immediate future. More- 

 over, it must be kept in mind that a number of reactors with SNF removed were dumped at sea 

 without the creation of any additional protective barriers to the release of radionuclides into the 

 marine environment. 



The aforesaid also applies to containerized SRW, and to RW dumped in the holds of sunken 

 vessels. According to calculations, the container walls (3-4 mm of steel 3) could be subject to 

 significant corrosion within 20-30 years af^er dumping at seal. Since the corrosion of steel 3 

 would proceed unevenly over the surface of the container, the flushing of its contents will not be 

 uniform. In that period, all radionuclides with half-lives shorter than 3 years will decay, and '^'Sr 

 and '^^Cs activity in the waste will decline by half 



The rate of release of the remaining long-lived radionuclides seems impossible to estimate 

 with certainty, although there is no doubt that the process will inevitably take a long time. 



Unfortunately, even these theoretical calculations could be far from reality. We know from 

 eyewitness testimony that during the disposal of low-level SRW, cases were noted when metal 

 containers were shot to accelerate their sinking. This means that without the slightest doubt, tHe 

 release of radionuclides began immediately ailer disposal of the containers. The radioecological 

 consequences of the release of large amounts of radionuclides in the shallow areas of the Kara Sea 

 must have affected the ecosystems, but this effect can be assessed only after observations are 

 made in the disposal areas. 



For now, we have only some alarming data indicating that in a number of water areas in the 



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