Radioactive wastes disposal at sea

The first ocean dumping of radioactive waste was conducted by the USA in 1946 some 80 km off the coast of California. The International Atomic Energy Agency (IAEA) published in August 1999 an Inventory of radioactive waste disposal at sea according to which the disposal areas and the radioactivity can be listed as shown in Table 1. 

The majority of the waste disposed consists of solid waste in various forms and origin, only 1.44% of the total activity is contributed by low-level liquid waste. The disposal areas in the north-east Atlantic and the Arctic contain about 95% of the total radioactive waste disposed at sea. 

IAEA (1999) Inventory of Radioactive Waste Disposals at Sea. IAEA-TECDOC-1105 Vienna International Atomic Energy Agency, pp. 24 A.1-A.22. 

Government Commission on Matters Related to Radioactive Waste Disposal at Sea ("Yablokov Commission"), created by Decree No. 613 of the Russian Federation President, Oct. 24, 1992, Facts and Problems Related to Radioactive Waste Disposal in Seas Adjacent to the Territory of die Russian Federation (Moscow, 1993) (quoted as Yablokov). 

According to Article I of [3] the aim of the convention is to prevent the pollution of the sea by dumping of waste and other matter that are liable to create hazards to hmnan health, to harm hving resources and marine life, to damage amenities or to interfere with other legitimate uses of the sea . Dumping is in Article III defined as (i) any deliberate disposal at sea of wastes or other matter from vessels, aircraft, platform or other man-made structures at sea and (ii) any deliberate disposal at sea of vessels, aircraft, platforms or man-made structures at sea . Article IV states that the dumping of wastes or other material listed in Aimex I is prohibited , and Annex I includes Radioactive wastes or other radioactive matter . From these Articles it seems obvious that the Convention applies to nuclear submarines. 

Steel drums containing solid radioactive wastes being loaded aboard U.S. Navy ship for disposal at sea. (Credit National Archives)... 

The safe disposal of the radioactive wastes from nuclear reactors is an important and controversial matter. A variety of proposals have been made, including the burial of radioactive waste in deep mines on either a recoverable or a permanent basis, burial at sea, and launching the waste into outer space. The first alternative is the only one that appears credible. The essential requirement is that the disposal site(s) be stable with respect to possible earthquakes or invasion by underground water. Spent nuclear fuel can be encased in blocks of borosilicate glass, packed in metal containers, and buried in stable rock formations. For a nuclide such as whose half-life is 24,000 years, a storage site that is stable over... 

There is some consideration of ultimately disposing of these bottles into the sea. This may be well justified because of the relatively short half-life, the low radiotoxicity, and the chemical inertness of Kr. It may even reduce the Kr hazard in comparison with surface storage of high-pressure bottles. At present, however, the London Convention on sea disposal of radioactive waste permits only disposal of solid waste. 

Compared to other wastes disposed of at sea the amount of radioactive waste by weight is rather diminutive. However, contrary to most of the ordinary wastes in the sea, detectable amounts of anthropogenic radioactivity are found in all parts of the world oceans and will continue to contaminate the sea for many thousands of years to come. This means that anthropogenic radioactive material has become an extra chronic radiation burden for marine organisms. In addition, the release of natural occurring radionuclides from offshore oil and gas production will gradually increase the levels of radium, in particular, with a possible, at present unknown, effect. 

However, marine food is not, and probably never will be, contaminated at a level that represents any danger to consumers. The ocean has always received debris from human activities and has a potential for receiving much more and thereby help to solve the waste disposal problems of humans. But as soon as a waste product is released and diluted in the sea it is almost impossible to retrieve. Therefore, in principal, no waste should be disposed of in the sea without clear documentation that it will never create any damage to the marine environment and its living resources. This means that with present knowledge no radioactive wastes should be allowed to be released into the sea. 

Of the discarded marine reactors, six of the 16 contained their spent nuclear fuel (SNF). In addition, approximately 60% of the SNF from one of the three icebreaker reactors was disposed of in a reinforced concrete and stainless steel (SS) shell container. The vast majority of the low and intermediate level solid radioactive waste was disposed of in containers of unknown composition. The Kara Sea disposal sites for the 16 marine reactors and low and intermediate level solid radioactive waste varied in depth from 12 to 380 m. In particular, the icebreaker reactors and part of their SNF were reportedly disposed of in Tsivolka Fjord at an estimated depth of 50 m. 

Liquid waste is generated in numerous places with activities <0.1 GBq/ m. Such waste is classified as low level. Some of these liquids may be clean enough to be released directly into the environment. Others are cleaned by flocculation, ion exchange, sorption, and similar processes. The general philosophy for liquid wastes is to concentrate all radioactivity to the next higher level because the waste volumes decrease in the order LLLW > MLLW > HLLW. Thus, in principle, the three kinds of wastes are reduced to two (HLLW and MLLW) and cleaned aqueous effluent. The MLLW and residues from LLLW cleaning are treated as the wastes of the nuclear power stations, i.e. concentrated and put into a disposal matrix such as concrete or bitumen (see 20.4.3). At some coastal sites it has been the practice to release the LLLW to the sea, with official permission. The nuclides of main concern are H, °Sr, Cs, Ru, and the actinides. 

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