Ocean disposal of radioactive waste

Data are from IAEA-TECDOC-1105, • 1972 Adoption of the Convention on the Prevention of Marine Pollution by Dumping of Wastes and Other Matter (London Convention 1972) • 1975 The London Convention 1972 entered into force (Prohibition of dumping of high level radioactive waste.) • 1978 On the 24 January a satellite named Kosmos 954 failed. It was powered by a liquid sodium–potassium thermionic converter driven by a nuclear reactor containing around 50 kilograms (110 lb) of uranium-235. • 1983 Moratorium on low-level waste dumping • 1988 Assessing the Impact of Deep Sea Disposal of Low-level Radioactive Waste on Living Marine Resources. IAEA Technical Reports Series No. 288 • 1990 Estimation of Radiation Risks at Low Dose. IAEA-TECDOC-557 • 1993 Russia reported the dumping of high level nuclear waste including spent fuel by former USSR. • 1994 (February 20) Total prohibition of disposal at sea came into force == 1946–1993 ==

Data are from IAEA-TECDOC-1105. • 1986 Chernobyl disaster total release – 12,060×1015 Bq. • 2011 Fukushima Daiichi nuclear disaster, estimated total 340×1015 to 780×1015 Bq, with 80% falling into the Pacific Ocean. • Fukushima Daiichi nuclear plant cooling water dumped (leaked) to the sea – TEPCO estimate 4.7×1015 Bq, Japanese Nuclear Safety Commission estimate 15×1015 Bq, French Nuclear Safety Committee estimate 27×1015 Bq. • Naturally occurring Potassium 40 in all oceans – 14,000,000×1015 Bq. • One container (net 400 kg) of vitrified high-level radioactive waste has an average radioactivity of 4×1015 Bq (Max 45×1015 Bq). Types of waste and packaging Data are from IAEA-TECDOC-1105. Liquid waste • unpackaged and diluted in surface waters • contained in package but not solidified Solid waste • low level waste like resins, filters, material used for decontamination processes, etc., solidified with cement or bitumen and packaged in metal containers • unpackaged solid waste, mainly large parts of nuclear installations (steam generators, pumps, lids of reactor pressure vessels, etc.) Reactor vessels • without nuclear fuel • containing damaged spent nuclear fuel solidified with polymer agent • special container with damaged spent nuclear fuel (icebreaker Lenin by the former Soviet Union) Dump sites Data are from IAEA-TECDOC-1105. There are three dump sites in the Pacific Ocean. Arctic Mainly at the east coast of Novaya Zemlya at Kara Sea and relatively small proportion at Barents Sea by the Soviet Union. Dumped at 20 sites from 1959 to 1992, total of 222,000 m3 including reactors and spent fuel. North Atlantic Dumping occurred from 1948 to 1982. The UK accounts for 78% of dumping in the Atlantic (35,088 TBq), followed by Switzerland (4,419 TBq), the United States (2,924 TBq) and Belgium (2,120 TBq). Sunken Soviet nuclear submarines are not included; see List of sunken nuclear submarines There were 137,000 tonnes dumped by eight European countries. The United States reported neither tonnage nor volume for 34,282 containers. Pacific Ocean The Soviet Union 874 TBq, US 554 TBq, Japan 606.2 Tonnes, New Zealand 1+ TBq. 751,000 m3 was dumped by Japan and the Soviet Union. The United States reported neither tonnage nor volume of 56,261 containers. Dumping of contaminated water at the 2011 Fukushima nuclear accident (estimate 4,700–27,000 TBq) is not included. Sea of Japan The Soviet Union dumped 749 TBq. Japan dumped 15.1 TBq south of main island. South Korea dumped 45 tonnes (unknown radioactivity value). == Environmental impact ==

Data are from IAEA-TECDOC-1105. Arctic Ocean Joint Russian-Norwegian expeditions (1992–94) collected samples from four dump sites. At immediate vicinity of waste containers, elevated levels of radionuclide were found, but had not contaminated the surrounding area. North-East Atlantic Ocean Dumping was undertaken by UK, Switzerland, Belgium, France, the Netherlands, Sweden, Germany and Italy. IAEA had been studying since 1977. The report of 1996, by CRESP suggests measurable leakages of radioactive material, and, concluded that environmental impact is negligible. North-East Pacific Ocean, North-West Atlantic Ocean dump sites of USA These sites are monitored by the United States Environmental Protection Agency and US National Oceanic and Atmospheric Administration. So far, no excess level of radionuclides was found in samples (sea water, sediments) collected in the area, except the sample taken at a location close to disposed packages that contained elevated levels of isotopes of caesium and plutonium. North-West Pacific Ocean dump sites of the Soviet Union, Japan, Russia, and Korea The joint Japanese-Korean-Russian expedition (1994–95) concluded that contamination resulted mainly from global fallout. The USSR dumped waste in the Sea of Japan. Japan dumped waste south of the main island. == Policies ==

The first conversations surrounding dumping radioactive waste into the ocean began in 1958 at the United Nations Law of the Sea Conference (UNCLOS). The conference resulted in an agreement that all states should actively try to prevent radioactive waste pollution in the sea and follow any international guidelines regarding the issue. By this time, governments began to realize the severe impacts of marine pollution, which led to one of the first international policies regarding ocean dumping in 1972 – the London Convention. The most recent version of the London Convention now bans all materials from marine dumping, except a thoroughly researched list of certain wastes. It also prohibits waste from being exported to other countries for disposal, as well as incinerating waste in the ocean. While smaller organizations like the Nuclear Energy Agency of the European Organization for Economic Cooperation and Development have produced similar regulations, the London Convention remains the central international figure of radioactive waste policies. Although there are many existing regulations that ban ocean dumping, it is still a prevalent issue. Different countries enforce the ban on radioactive waste dumping on different levels, resulting in an inconsistent implementation of the agreed upon policies. Because of these discrepancies, it is hard to judge the effectiveness of international regulations like the London Convention. == Ocean floor disposal ==

Ocean floor disposal is a method of sequestering radioactive waste in ocean floor sediment where it is unlikely to be disturbed either geologically or by human activity. Several methods of depositing material in the ocean floor have been proposed, including encasing it in concrete and as the United Kingdom has previously done, dropping it in torpedoes designed to increase the depth of penetration into the ocean floor, or depositing containers in shafts drilled with techniques similar to those used in oil exploration. Ocean floor sediment is saturated with water, but since there is no water table per se and the water does not flow through it the migration of dissolved waste is limited to the rate at which it can diffuse through dense clay. This is slow enough that it could potentially take millions of years for waste to diffuse through several tens of meters of sediment so that by the time it reaches open ocean it would be highly dilute and decayed. Large regions of the ocean floor are thought to be completely geologically inactive and it is not expected that there will be extensive human activity there in the future. Water absorbs essentially all radiation within a few meters provided the waste remains contained. One of the problems associated with this option includes the difficulty of recovering the waste, if necessary, once it is emplaced deep in the ocean. Also, establishing an effective international structure to develop, regulate, and monitor a sub-seabed repository would be extremely difficult. Beyond technical and political considerations, the London Convention places prohibitions on disposing of radioactive materials at sea and does not make a distinction between waste dumped directly into the water and waste that is buried underneath the ocean's floor. It remained in force until 2018, after which the sub-seabed disposal option can be revisited at 25-year intervals. Depositing waste, in suitable containers, in subduction zones has also been suggested. Here, waste would be transported by plate tectonic movement into the Earth's mantle and rendered harmless through dilution and natural decay. Several objections have been raised to this method, including vulnerabilities during transport and disposal, as well as uncertainties in the actual tectonic processes. ==See also==