The Soviet nuclear submarine Komsomolets, which sank off Norway in 1989, remains under scrutiny after Norwegian researchers reported continuing radioactive leaks from the wreck.
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Wreck Raises Long-Running Concerns
The submarine lies close to 1.7km, or about one mile, below the Norwegian Sea. Its sinking prompted alarm because two nuclear-tipped torpedoes were left on board, containing about 9lb (4kg) of plutonium.
In a 1993 BBC report, Russian Greenpeace activist Dimitri Litvinov warned that the wreck posed an urgent danger if nothing was done. At the time, environmentalists feared plutonium could enter rich fishing grounds, although an international scientific report that year concluded fisheries were unlikely to be contaminated.
Fire And Sinking
Komsomolets was built as an advanced Soviet attack submarine capable of operating at exceptional depths. Nato expected it could be the first of a larger class, but no sister vessels were completed. A 1994 BBC Horizon documentary described it as a submarine designed to cruise and launch nuclear weapons from 1,000m, far deeper than Western equivalents could operate.
A fire broke out on 7 April 1989. The crew brought the vessel to the surface, but it sank after five hours afloat. Forty-two of the 69 crew members died.
As the submarine went down, an escape pod carried five trapped sailors to the surface. Only one managed to get out before the pod filled with water.
When the wreck struck the seabed, an explosion tore open its titanium pressure hull and allowed seawater to reach the nuclear torpedoes. Russian oceanographers later found parts of the hull had shattered in the blast.
Scientists disagreed over the scale of the threat. Igor Spassky, from the Rubin Institute, which designed the submarine, told the BBC in 1993 that the situation was not catastrophic, but said he wanted the wreck raised. He also warned separately that saltwater corrosion could eventually release plutonium from the damaged torpedoes.
Attempts To Contain Material
Deep-sea engineering work in 1995 and 1996 sealed cracks in the hull and closed torpedo tubes to contain radioactive material. The operation ended in July 1996.
Norwegian government investigations have since found the submarine is still leaking. The sealant used in the 1990s was expected to last about 30 years.
A March 2026 report by the Norwegian Radiation and Nuclear Safety Authority, known as the DSA, said the torpedoes remain sealed but the reactor is deteriorating. Researchers found radioactive material escaping in occasional bursts, including a visible cloud from a ventilation duct, rather than as a constant leak.
Ingar Amundsen, acting director of the DSA's Department for International Nuclear Safety and Security, said current releases from the reactor had so far had little effect on the surrounding marine environment.
Calls For Further Checks
Experts say the risk could change as corrosion continues. Hans Kristensen, director of the Nuclear Information Project at the Federation of American Scientists, told the BBC that radiation levels could be affected by oxygen levels in seawater around and inside the wreck, as well as by the condition of the sealant.
He said shifting currents could influence how radioactive material moves from the wreck and whether it reaches bottom-feeding species and fish. He added that the earlier decision to seal the submarine showed authorities had recognised the risk.
Amundsen said more work was needed to understand the releases and corrosion, but the depth of the wreck made mitigation difficult and there were no known current plans for action. Kristensen said a new expedition should at least assess the submarine’s condition, noting that plutonium in warheads has a half-life of 24,000 years.
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14 July 2026
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