Ocean disposal of radioactive waste

From 1946 through 1993, thirteen countries used ocean disposal or ocean dumping as a method to dispose of nuclear/radioactive waste. The waste materials included both liquids and solids housed in various containers, as well as reactor vessels, with and without spent or damaged nuclear fuel. Since 1993, ocean disposal has been banned by international treaties. (London Convention (1972), Basel Convention, MARPOL 73/78)
"Ocean floor disposal" (or sub-seabed disposal)—a more deliberate method of delivering radioactive waste to the ocean floor and depositing it into the seabed—was studied by the United Kingdom and Sweden, but never implemented.
History.
Data are from IAEA-TECDOC-1105, pages 3–4.
1946–1993.
Data are from IAEA-TECDOC-1105. Summary of pages 27–120:
Disposal projects attempted to locate ideal dumping sites based on depth, stability and currents, and to treat, solidify and contain the waste. However, some dumping only involved diluting the waste with surface water, or used containers that imploded at depth. Even containers that survived the pressure could physically decay over time.
The countries involved – listed in order of total contributions measured in TBq (TBq=1012 becquerel) – were the Soviet Union, the United Kingdom, Switzerland, the United States, Belgium, France, the Netherlands, Japan, Sweden, Russia, New Zealand, Germany, Italy and South Korea. Together, they dumped a total of 85,100 TBq (85.1x1015 Bq) of radioactive waste at over 100 ocean sites, as measured in initial radioactivity at the time of dump.
For comparison:
Types of waste and packaging.
Data are from IAEA-TECDOC-1105.
Dump sites.
Data are from IAEA-TECDOC-1105.
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.